6,301 research outputs found

    Status and prospects of `bi-large' leptonic mixing

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    Bi-large patterns for the leptonic mixing matrix are confronted with current neutrino oscillation data. We analyse the status of these patterns and determine, through realistic simulations, the potential of upcoming long-baseline experiment DUNE in testing bi-large \emph{ansatze} and discriminating amongst them.Comment: 14 pages, 7 figures, numerical results refined, some more discussion added. Matches published version of Phys. Let.

    Lepton flavor violating μ→eγ\mu\to e\gamma and μ−e\mu-e conversion in unparticle physics

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    We have studied lepton flavor violation processes μ→eγ\mu\to e\gamma and μ−e\mu-e conversion in nuclei induced by unparticle. Both Br(μ→eγ){\rm Br}(\mu\to e\gamma) and μ−e\mu-e conversion rate CR(μ−e,Nuclei){\rm CR}(\mu-e,{\rm Nuclei}) strongly depend on the scale dimension dUd_{\cal U} and the unparticle coupling λKff′\lambda^{ff'}_{\rm K}(K=V, A, S, P). Present experimental upper bounds on Br(μ→eγ){\rm Br}(\mu\to e\gamma), CR(μ−e,Ti){\rm CR}(\mu-e,{\rm Ti}) and CR(μ−e,Au){\rm CR}(\mu-e,{\rm Au}) put stringent constraints on the parameters of unaprticle physics. The scale dimensions dUd_{\cal U} around 2 are favored for the unparticle scale ΛU\Lambda_{\cal U} of O(10TeV){\cal O}(10 {\rm TeV}) and the unparticle coupling of O(10−3){\cal O}(10^{-3}). CR(μ−e,Nuclei){\rm CR}(\mu-e,{\rm Nuclei}) is proportional to Zeff4A2/Z\rm{Z^4_{eff}A^2/Z} for the pure vector and scalar couplings between unparticle and SM fermions, this peculiar atomatic number dependence can be used to distinguish unparticle from other theoretical models.Comment: 16 pages, 5 figure

    The Correlation Between Spectral Index And Accretion Rate For AGN

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    In this paper, we present a correlation between the spectral index distribution (SED) and the dimensionless accretion rate defined as m˙=Lbol/LEdd\dot{m}={L_{bol}/L_{Edd}} for AGN. This quantity is used as a substitute of the physical accretion rate. We select 193 AGN with both broad Hα\alpha and broad Hβ\beta, and with absorption lines near MgIλ5175A˚\lambda5175\AA from SDSS DR4. We determine the spectral index and dimensionless accretion rate after correcting for both host galaxy contribution and internal reddening effects. A correlation is found between the optical spectral index and the dimensionless accretion rate for AGN, including low luminosity AGN (LHα<1041erg⋅s−1L_{H\alpha}<10^{41}{\rm erg\cdot s^{-1}} sometimes called "dwarf AGN" (Ho et al. 1997)). The existence of this correlation provides an independent method to estimate the central BH masses for all types of AGN. We also find that there is a different correlation between the spectral index and the BH masses for normal AGN and low luminosity AGN, which is perhaps due to the different accretion modes in these two types of nuclei. This in turn may lead to the different correlations between BH masses and optical continuum luminosity reported previously (Zhang et al. 2007a), which invalidates the application of the empirical relationship found by Kaspi et al. (2000, 2005) to low luminosity AGN in order to determine their BLR sizes.Comment: 10 pages, 7 figures, accepted for publication in MNRA

    Generalized μ−τ\mu-\tau reflection symmetry and leptonic CP violation

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    We propose a generalized μ−τ\mu-\tau reflection symmetry to constrain the lepton flavor mixing parameters. We obtain a new correlation between the atmospheric mixing angle θ23\theta_{23} and the "Dirac" CP violation phase δCP\delta_{\rm CP}. Only in a specific limit our proposed CP transformation reduces to standard μ−τ\mu-\tau reflection, for which θ23\theta_{23} and δCP\delta_{CP} are both maximal. The "Majorana" phases are predicted to lie at their CP-conserving values with important implications for the neutrinoless double beta decay rates. We also study the phenomenological implications of our scheme for present and future neutrino oscillation experiments including T2K, NOν\nuA and DUNE.Comment: 14 pages, 9 figures, latex, Final version to appear in Physics Letters

    CP Symmetries as Guiding Posts: revamping tri-bi-maximal Mixing. Part II

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    In this follow up of arXiv:1812.04663 we analyze the generalized CP symmetries of the charged lepton mass matrix compatible with the complex version of the Tri-Bi-Maximal (TBM) lepton mixing pattern. These symmetries are used to `revamp' the simplest TBM \textit{Ansatz} in a systematic way. Our generalized patterns share some of the attractive features of the original TBM matrix and are consistent with current oscillation experiments. We also discuss their phenomenological implications both for upcoming neutrino oscillation and neutrinoless double beta decay experiments.Comment: 19 pages, 8 figures. Title change to match the first par

    Phase-field-crystal modeling of the (2x1)-(1x1) phase-transitions of Si(001) and Ge(001) surfaces

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    We propose a two-dimensional phase-field-crystal model for the (2×\times1)-(1×\times1) phase transitions of Si(001) and Ge(001) surfaces. The dimerization in the 2×\times1 phase is described with a phase-field-crystal variable which is determined by solving an evolution equation derived from the free energy. Simulated periodic arrays of dimerization variable is consistent with scanning-tunnelling-microscopy images of the two dimerized surfaces. Calculated temperature dependence of the dimerization parameter indicates that normal dimers and broken ones coexist between the temperatures describing the charactristic temperature width of the phase-transition, TLT_L and THT_H, and a first-order phase transition takes place at a temperature between them. The dimerization over the whole temperature is determined. These results are in agreement with experiment. This phase-field-crystal approach is applicable to phase-transitions of other reconstructed surface phases, especially semiconductor n×n\times1 reconstructed surface phases.Comment: 10 pages with 4 figures include

    The Relation of Thermal Fluctuation and Information-Entropy for One-Dimensional Rindler Oscillator

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    Within the framework of thermo-field-dynamics (TFD), the information-entropies associated with the measurements of position and momentum for one-dimensional Rindler oscillator are derived, and the connection between its information-entropy and thermal fluctuation is obtained. A conclusion is drawn that the thermal fluctuation leads to the loss of information.Comment: 14 pages, 1 figur
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